The widespread use of sliding glass doors and windows in modern homes has brought with it serious security problems. The latch mechanisms conventionally employed in sliding glass doors are often readily susceptible to unauthorized forced opening. Such latch mechanisms often include a hook-like latching or draw bar, and the sliding glass doors can often be lifted on their guide tracks to allow unhooking of the latch bar.
A further problem in connection with many sliding glass door latch mechanisms has been that they are not capable of being locked and unlocked from outside the door. In large apartment houses it is not uncommon for one side of the apartment house to have front or entry doors, with the opposite side of the apartment house having sliding glass doors. The side of the apartment house with the sliding glass doors, however, also often includes the garage structures. Thus, the resident of the apartment house must lock the sliding glass door from the inside, leave his apartment from the front door, and walk all the way around the building to the back where the garage is located. This procedure, of course, is reversed upon his return, and could be short-circuited with much improved convenience if the sliding glass door could be locked and unlocked from the outside thereof.
The prior art does include plug-in latch mechanisms of the type in which a latching bar or element is inserted into a keeper assembly until it is in a latched position which is held against withdrawal by the keeper assembly. Such prior art also teaches the rotatable mounting of the latch bar for release of the same from the keeper assembly. U.S. Pat. Nos. 554,701, 1,836,970, 1,875,768, 1,967,627, 2,118,729, 2,486,003, 3,026,702 and 3,133,168 are illustrative of prior art found in connection with a search of the present invention which disclose plug-in type latch mechanisms which are rotatable to effect release, but which do not disclose the improved latch mechanism of the present invention.